Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:44:12: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (*it != f [x] && graph2 [*it]) ^ user.cpp: In function ‘int main()’: user.cpp:62:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("graf.in", "r", stdin); ^ user.cpp:63:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("graf.out", "w", stdout); ^ user.cpp:65:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d%d", &n, &m, &a, &b); ^ user.cpp:67:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &x, &y); ^